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What is Reverse Osmosis Water? Everything You Need to Know

Despite what you may think, most tap water contains a variety of possible contaminants that can be harmful to your health.

Reverse osmosis water is the result of removing contaminants from your drinking water with a reverse osmosis membrane (filter).

This article will provide you with everything you need to know about reverse osmosis (RO) water and why it is a safe and effective way to clean contaminated water.

reverse osmosis water

What is reverse osmosis?

In nature, the reverse osmosis process takes place in cells where water is moved into the cell via a part of the cell called an osmotic membrane.

This semipermeable membrane absorbs most of the water molecules but forces other particles through it to separate them out from cellular fluids through osmotic pressure.

This natural process results in only pure water on one side of the membrane while all of the solids end up on the other side.

Reverse osmosis filtration is a process that removes contaminants from the water in a similar way using a water filter.

A reverse osmosis system will remove up to 99% of all contaminants found in tap water.

This includes:

The RO process also removes harmful bacteria like E-coli and Salmonella.

The result is pure, clean drinking water that tastes great!

How does reverse osmosis work?

reverse osmosis process
How a reverse osmosis membrane works

Reverse osmosis water filtration separates contaminants from water by using high pressure to push water through a super fine reverse osmosis membrane, leaving all contaminants behind.

The reverse osmosis membrane is made from a semi-permeable material that only allows water to pass through, so the contaminants are unable to penetrate it.

The same high-water pressure is used to flush the blocked chemicals from the RO membrane and then wash them down the drain.

A reverse osmosis filtration system is actually a series of filters, and the water passes through all of them to ensure the purest drinking water.

Common filters that work together to improve water quality include:

  • Sediment filter to remove large particles from the water such as sand and silt
  • At least one carbon filter to remove chlorine and organic chemicals
  • The RO membrane removes smaller contaminants down to just 15 nanometers in size
  • Additional activated carbon filters remove any remaining impurities, odors, and bad tastes

Optional filters can be added, such as UV (Ultraviolet light), which destroys any microorganisms that may be present in contaminated water. This is especially important if your drinking water comes from a natural source such as surface water or a well.

What is reverse osmosis water?

Reverse osmosis water is simply water that has been through the process of water filtration by a reverse osmosis filter.

Total dissolved solids (TDS), pollutants, chemicals, and other contaminants are all removed to improve water quality and provide better fresh water.

Many producers of food, beverages, and bottled water use large scale RO membranes to remove health related contaminants from their feed water sources.

Benefits of reverse osmosis water

There are many benefits to clean, pure reverse osmosis filtered water.

It can be used for drinking, cooking, and even watering plants without any worry about dangerous chemicals.

Reverse osmosis differs from a basic water filtration system (like carbon filtration pitchers) since the water purification process is so much more effective. An RO system often includes a carbon filter as part of the process to produce the most purified water.

Drawbacks of reverse osmosis water

Some people are quick to point out that a reverse osmosis water system removes too much from the treated water, including beneficial minerals needed by the human body.

This is true. Reverse osmosis works VERY well to produce pure drinking water and it does not pick and choose what is removed. Reverse osmosis also removes minerals that people may need from the feed water.

If your diet is low on minerals and you rely on what is in your drinking water for dissolved minerals, you may not get enough if you only drink reverse osmosis water.

That’s why many experts recommend adding some healthy minerals (such as calcium carbonate) back in after the filtration process so that these important nutrients aren’t lost. This accomplished with a remineralization filter, which is a low-cost optional add-on for many RO systems to produce filtered alkaline water.

After the water is filtered and the reverse osmosis unit removes beneficial minerals, the RO water passes through a bed of natural minerals and picks up trace amounts before you use it. This gives the reverse osmosis drinking water more of a mineral water taste and feel.

Otherwise, people who eat a well-rounded diet will usually get these minerals from other sources, so it is not necessary to have high mineral levels in drinking water.

How much water does reverse osmosis waste?

reverse osmosis waste

Reverse osmosis does waste some water as part of the process.

Contaminants are all trapped on one side of the reverse osmosis membranes and the system uses the pressure of the incoming water to flush those blocked particles down the drain.

In a home RO water system, you can expect to see a waste ratio of between 1:1 to 1:4. This means 1 gallon of pure water to 1 gallon of wastewater up to 1 gallon of pure water to 4 gallons of wastewater.

If you care about conserving water or pay for your municipal water, there is a big advantage to choosing a system with a low waste water ratio and high efficiency.

The systems that are the most efficient and waste the least water usually have some sort of passive or electric high-pressure pump built in that maintains proper input pressure on the RO membrane.

Is reverse osmosis water safe?

Yes. Drinking RO water is very safe (according to the CDC and many other sources)

The purpose of an RO filter is to remove impurities from your water, and it does an excellent job at this.

Unless you remineralize the filtered water to add back beneficial minerals, RO filters don’t add anything to the water.

Once filtered, reverse osmosis water is more clean and pure than it started.

Who should consider reverse osmosis drinking water?

reverse osmosis drinking water

Tap water in the United States can have a lot of harmful contaminants in it.

Even municipal water supplies have been in the news for being contaminated, such as the recent lead poisoning in Flint, Michigan, and other cities, PFAS “forever” chemicals in communities everywhere, and pharmaceuticals that enter the water supply.

If you have a private well, it’s probably not any better because wells are often contaminated with bacteria and nitrates that come from agriculture and other sources of pollution.

Installing a water filter at home is considered a standard upgrade in many locations and by some home improvement experts.

A reverse osmosis filter is an excellent choice for anyone who wants to improve their health by reducing exposure to unhealthy substances found in tap water like arsenic, fluoride, volatile organic compounds (VOCs), pesticides, and herbicides.

A point-of-use filtration system will provide a dedicated faucet for filtered water and a whole house system would provide cleaner water to all of your points-of-use.

“Hard water” is common water quality issue no matter where your tap water comes from. While reverse osmosis will remove some of these hard minerals, you may need a water softener as a specific water treatment for this issue.

Reverse osmosis drinking water is also appropriate if someone has compromised immune system or other medical conditions which might need special attention with regards to what they drink on a daily basis. According to studies, chronic kidney disease patients should use purified water instead of tap water because their natural filtering mechanisms are impaired.

Should you get a reverse osmosis water filter?

Is reverse osmosis water safe?

Everyone should consider a system that will produce reverse osmosis drinking water!


  • Keeps you and your family safe
  • Reduces your exposure to dangerous substances by up to 99%
  • Eliminates odors and tastes of chlorine, as well as pesticides, bacteria, microorganisms, and heavy metals
  • No more spending money and energy on bottled water
  • You can get all the clean, pure water you need at home

Reverse osmosis water is a great option for those looking to get pure and clean drinking water at home.

If your family drinks a lot of bottled or tap water every day, it makes sense to investigate an RO filter in order to avoid exposure to harmful toxins like chlorine and lead.

And don’t worry – reverse osmosis systems aren’t expensive! You’ll find affordable options online with reviews from happy customers who have had success using them in their homes too.